This invention relates to the detection of leaks in pipes. In particular, this invention is a method and means of detecting the location of a leak in a buried pipe containing a fluid by analysis of the acoustical signals produced in the pipe or the fluid by the leak.
When fluids under pressure are contained or carried in buried pipes, a small local failure of the pipe causes two problems. One problem is to detect the fact that there is a leak; the other is to locate the leak to fix it. As a general rule, it may be stated that the smaller the leak, the more difficult it is to detect the presence of the leak and the more difficult it is to locate such a leak even if its presence is known. In some systems of water pipes a principal method of leak detection involves noticing the collapse of ground over a buried water pipe as a result of subsurface erosion from a leak. Such a method of detection is obviously undesirable in the case of expensive fluids that are carried in the pipes or of fluids that are corrosive or flammable. For many years natural gas has been doped with chemicals having strong odors to assist in the location of leaks. Such a method of leak detection, however, is of most use in the absence of pavement over the pipe. Pipe that is buried under concrete or other paving and that carries a corrosive or flammable substance presents a challenge that is not met by any of the detection systems just described.
Various types of active acoustic systems serve to detect leaks by exciting acoustic waves in the pipe or in the fluid conveyed in the pipe. Acoustic detectors are placed to detect signals produced by the discontinuities at the leak, either by responding to reflections generated by the discontinuity or by detecting differences produced in transmitted signals by the discontinuity in the pipe. Such systems, however, generally require substantial breaks in the pipes to generate signals that are large enough to be detected in the presence of the exciting signals.
It is an object of the present invention to provide a better method and means of detecting leaks in buried pipes.
It is a further object of the present invention to provide a method and means of locating leaks in buried pipes.
It is a further object of the present invention to provide a method and means of detecting leaks in pipes carrying fluids under pressure.
Other objects will become apparent in the course of a detailed description of the invention.